Synthesis and application of conjugated polymers
containing perylene building blocks
Abstract
Compared with fluorescent small molecules,fluorescent conjugated polymers have been widely used in sensing and biological fields because of their many advantages,such as structural modifiability,processability and high sensitivity.Over the past several decades,different fluorescent conjugated polymers have been successfully synthesized with different emission colors.Fluorescent conjugated polymers with longer emission wavelength have many advantages in biological field,such as the ability to eliminate the interference from their own fluorescent substances,the lower energy required for excitation light source and less damage to biological samples.Moreover,the water-soluble conjugated polymers have many advantages for sensing application in aqueous enviroment, thus the design and synthesis of these conjugated polymers are of practical significance.
In this paper,a series of orange-yellow fluorescent conjugated polymers containing perylene building blocks with side chains in different lengths were designed and synthesized;their structures and photophysical properties were characterized.Then,these polymers were selectively hydrolyzed and the
polymers with various carboxylic acid groups were obtained.Finally,the sensing applications of these polymers were studied.
1.Five new conjugated polymers,poly(perylene-alt-phenyleneethynylene)s(PPPEs) with the same backbone and multi similar ester-group-containing side chains in various lengths,were synthesized via Sonogashira coupling reaction.These polymers were characterized by1H NMR,FTIR,GPC,elemental analysis,UV spectra and fluorescence spectra,and the results confirmed that we successfully synthesized these polymers with different side chain lengths.These polymers have good solubility in common organic solvents.These polymers are slightly different in the degree of polymerization and the fluorescence quantum yield,likely due to the subtle impacts of the different length of the side chains on the polymerization process and solubility.Two comonomers with different
III包场中学
ester groups(aromatic esters and aliphatic esters)were designed.After optimization of the hydrolysis conditions,we successfully realized the selective hydrolysis of the ester groups on the different building units;we obtained conjugated polymers containing carboxyl groups in different density.The resultant polymers were characterized by FTIR and elemental analysis.The partially hydrolyzed poly
mer are insoluble in common solvents, only the completely hydrolyzed polymer(PPPECOOH)can be dissolved in an alkaline aqueous solution.In future,we may take advantage of the solublity of the polymers before hydrolysis to fabricate them into solid materials in various forms;after hydrolysis,the polymers in solid materials will have good stability.
2.The PPPECOOH/CPV A fibrous membrane was prepared by elecrospinning of the blend of polyvinyl alcohol(PVA)and PPPECOONa followed by crosslinking and acidification;then it was treated with NaOH aqueous solution,resulting in PPPECOONa/CPV A fibrous membrane.The PPPECOOH/CPV A and PPPECOONa/CPV A fibrous membranes can be converted each other by treated with acidic or basic solutions; and the PPPECOOH/CPV A and PPPECOONa/CPV A membranes have very different colors under both natural light and UV light.0.2%PPPECOONa/CPVA fibrous membranes and1%PPPECOONa/CPVA fibrous membranes were prepared with PPPECOONa contents of0.2wt%and1wt%,respectively.The above two fibrous membranes were used to sensing the H2SO4aqueous solutions,by comparing the colors under natural light and UV light before and after contacting with H2SO4solutions with different pH values.First,the0.2%PPPECOONa/CPVA fibrous membrane was immersed in H2SO4aqueous solutions with different pH value for3min.The results showed that H2SO4solution with pH lower than
3.0could make the fluorescence of this fibrous membrane completely quenched.Then,under the same conditions, 1%PPPECOONa/CPV A fibrous membrane was used for the same purpose.The results showed that the H2SO4solutions with pH lower than
4.0could make the fluorescence of the fibrous membranes completely quenched.We anticipate that,by varying the percentage of PPPECOONa in the fibrous membrane,the sensing range of pH value of H2SO4aqueous
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solutions could be enlarged.In addition,the membranes can be reused for a certain times. Therefore,we believe these fibrous membrane can be used for the sensing the pH of acidic rain in the future.
3.Based on the characteristics of PPPEs,one of PPPEs was used to detect nitrobenzene(NB)and2,4-dinitrotoluene(DNT)with visible light(516nm)excitation. However,the result was unexpected that the fluorescence of this polymer almost had no response to NB and DNT.Then the excitation wavelength range(such as the excitation wavelength of350nm)commonly used in the literature was used to excite PPPEs for detection NB and DNT.The results showed that five PPPEs a
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ll had good response to NB and DNT with the excitation wavelength of350nm,with negligible difference.After that, several other conjugated polymers previously synthesized by our group were used to detect NB and DNT with the excitation wavelength of330nm or visible light wavelength,and the results were basically the same as those of PPPEs.In order to study the influence of the excitation wavelength on the response upon NB and DNT,several conjugated polymers above used and one fluorescent small molecule were selected to detect DNT,and the excitation wavelengths were set at270nm,290nm,310nm,330nm,350nm,370nm, 390nm,410nm,430nm and450nm,respectively.The results showed that the sensitivity toward DNT had a strong dependence on the excitation wavelength;and the shorter the excitation wavelength,the higher the sensitivity.Finally,the sensing mechanism was studied.The results showed that these polymers had a fluorescence inner filter effect on the detection process of NB and DNT;and the shorter the excitation wavelength,the stronger the absorption of NB and DNT,and the stronger the fluorescence inner filter effect.
Keywords:PAE(Poly(aryleneethynylene)),perylene building block,electrospinning, fluorescence sensing,inner filter effect
Written by:Heng Zhang
Supervised by:Prof.Li-Juan Fan
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目录
第一章综述 (1)
1.1聚亚芳香基乙炔撑类聚合物的合成方法 (2)
1.1.1Heck偶联反应 (2)
1.1.2Mortreux-Mori反应 (3)
1.1.3Stille偶联反应 (3)
1.1.4Sonogashira偶联反应 (4)
1.2.1光诱导电子转移 (7)
1.2.2能量转移 (7)
1.2.3光诱导电荷转移 (9)
1.2.4内滤效应 (9)
1.3荧光共轭聚合物在荧光化学传感器上的应用 (11)
1.3.1荧光共轭聚合物化学传感器在金属离子检测方面的应用 (12) 1.3.2荧光共轭聚合物化学传感器在生物分子检测方面的应用 (12)
1.3.3荧光共轭聚合物化学传感器在爆炸物检测方面的应用 (13)
1.3.4荧光共轭聚合物化学传感器在检测其他物质方面的应用 (14)
1.4静电纺丝 (15)
1.5课题的总体思路 (15)
第二章含苝构筑单元的聚亚芳香基乙炔撑类聚合物的合成及选择性水解研究 (17)
2.1引言 (17)
2.2实验部分 (18)
2.2.1试剂和仪器 (18)
2.2.2单体的合成 (19)ttg
2.2.3聚合物的合成 (22)
2.2.4聚合物的水解 (23)
2.3结果与讨论 (25)
2.3.1合成及表征 (25)
2.3.2聚合物的光物理性质 (30)
2.3.3聚合物的水解表征 (31)
2.4本章小结 (33)
救世军第三章PPPECOONa/CPVA荧光纤维膜的制备及其荧光传感性能研究 (35)
3.1引言 (35)
3.2实验部分 (36)
3.2.1试剂和仪器 (36)
3.2.2PPPECOONa/CPV A纤维膜的制备过程 (37)
3.2.3CPVA纤维膜的制备过程 (37)
3.2.4PPPECOONa/CPV A纤维膜对硫酸水溶液的检测过程 (37)
冯 卡门3.2.5PPPECOONa/CPV A纤维膜重复使用的处理过程 (38)
3.3结果与讨论 (38)
3.3.1光物理性质研究 (38)
3.3.2纤维膜的SEM表征 (40)
3.3.3纤维膜的接触角 (41)
3.3.40.2%PPPECOONa/CPV A纤维膜对硫酸水溶液的检测研究 (42)
3.3.51%PPPECOONa/CPV A纤维膜对硫酸水溶液的检测研究 (44)
3.3.6PPPECOONa/CPV A纤维膜对硫酸水溶液检测的重复使用性研究 (45)
3.3.7PPPECOONa/CPV A纤维膜对硫酸水溶液检测的时间依赖性研究 (46)
3.3.8纤维膜的紫外可见漫反射光谱研究 (47)
3.4本章小结 (48)
第四章聚亚芳香基乙炔撑类聚合物对硝基苯和2,4-硝基甲苯的传感检测研究 (49)
4.1引言 (49)
4.2实验部分 (51)
4.2.1试剂和仪器 (51)
4.2.2实验准备和操作 (51)文迪雅事件
4.3结果与讨论 (51)
4.3.1光物理性质 (51)
4.3.2溶液体系中硝基芳烃类分子的检测应用 (53)
4.3.3在不同波长光激发下，聚合物对DNT的检测结果 (61)
4.3.4聚合物对NB和DNT检测的机理研究 (62)
4.4本章小结 (66)
第五章结论与展望 (68)
5.1结论 (68)
5.2创新点 (69)
5.3展望 (70)
参考文献 (71)
符号及缩写 (85)
攻读学位期间的学术成果 (86)
致谢 (87)
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